Draining Central Heating System Vent/Feed Pipe

I live in a house that is 3 years old with an open vented central heating system.

I am trying to remove a radiator and was looking for the option of not draining down the system completely.

I was going to use bungs in the feed and vent pipe. When I looked at the expansion tank there appears to be no vent pipe hanging over the tank.. The boiler supports a combined a feed vent option but looking on the internet this looks to be an out of date practice.

Is it still possible to bung the single pipe as you would with the separate pipes and so not drain the system?

if its only the rad why not turn off both valves and then just drain the water from one side of the rad by 'cracking' the joint and opening the bleed valve, use a roasting dish or like to contain water and wrap an old towel around the bottom of pipe and on the floor to save carpet etc